This invention relates to lubrication system for a rotary machine, and more particularly, the invention relates to an axial screw pump for providing supplemental lubrication and cooling to an electromechanical rotary machine.
Hollow shafts have been used in pumps and other rotary machines to permit oil to flow to areas in need of lubrication. The shaft and other components induce oil flow in the shaft passage as resulting from rotation of the shaft. However, lubrication circulation from this type of configuration is often inadequate for providing sufficient lubrication and cooling to shaft bearings.
Screw type arrangements have been employed with rotating shafts to provide a lubricated hydrodynamic seal. The seal includes a pair of mating portions with complementary helical grooves to provide a lubricating film between the portions so that the seal can withstand high rotational speeds. Although the seal provides a pumping action of oil there through, the screw arrangement is not sufficient to provide lubrication and cooling throughout the rotary machine. Other screw arrangements have been used as a pump for pumping fluid throughout the rotary machine. However, prior art screw pumps have not been used in combination with a hollow shaft to provide increased lubrication and cooling throughout the rotary machine.
Therefore, what is needed is a rotary machine having increased internal lubrication and cooling.